Wire wrapping device



April 26, 1966 BQQMGAARD 3,248,062

WIRE WRAPPING DEVICE Filed Jan. 29, 1964 2 Sheets-Sheet 1 INVENTOR. PETER I? BOOMGAARD BY Z f A TOR/VEY April 26, 1966 P. F. BOOMGAARD 3, 8,0

WIRE WRAPPING DEVICE Filed Jan. 29, 1964 2 Sheets-Sheet 2 F I l: 7 F l c: 9

INVENTOR. PETER 5004404400 TOR/V27 United States Patent 3,248,062 WIRE WRAPPING DEVICE Peter F. Boomgaard, Spring Lake, Mich, assignor to Gardner-Denver Company, a corporation of Delaware Filed Jan. 29, 1964, Ser. No. 340,200 3 Claims. (Cl. 242-7) operated rotating means. At its free end, or forward end,

the bit is provided with a longitudinal terminal-receiving recess and a radially offset wire receiving groove. Typically, these prior art devices are intended to connect opposite end portions of a conductor to spaced terminals to establish an electrical circuit between the terminals. To this end, a bare end portionof the conductor is initially inserted into the wire receiving groove of the bit; and, in a well understood manner, the end portion is wrapped or drawn about a terminal in response to rotation of the bit about the terminal. To effect wrapping of the wire about the terminal, rotation of the conductor along with the bit must be restrained; therefore, at a point along its length located axially forwardly of the opening of the wire-receiving groove, the conductor is usually bent radially outwardly with respect to the axis of the bit and is seated in a notch formed in the forward end of the stationary sleeve.

A recently developed application for wrapped wire connections contemplates binding two or more terminals together to complete an electrical circuit. This type of connection is known as a bound joint and is formed when two sharp-edged terminals are secured together with their side surfaces in contact by wrapping a wire thereabout in tight helical convolutions. The wrapping wire of the bound joint is not necessarily intended to electrically connect the terminals bound thereby to any other terminal; and, in this respect, bound joints depart from conventional wrapped connections wherein a conductor has its opposite ends secured to spaced terminals.

Bound joints produced with conventional wire wrapping devices of the type described above have been unsatisfactory because the aforementioned outwardly bent portion of the wire which engages the sleeve to hold the wire against rotation with the bit forms a pigtail extending laterally from the terminal. The lateral extent of such pigtails may be sufficient to bring the same into unwanted shorting contact with an adjacent terminal or other circuit component. To avoid this occurrence, it has heretofore been necessary to bend the pigtail against the terminal or to cut it off. In either case, such a follow-up step decreases the efiiciency of the operation and substantially increases costs. In preparing for the wrapping operation, additional time and effort are conventionally consumed in manually bending the wire laterally for holding engagement with the sleeve.

Accordingly, as a general object, the present invention contemplates an improved wire wrapping device for bound terminals which will overcome the above noted deficiencies of known devices presently employed for this purpose.

Another object is to provide an improved sleeve for a wire wrapping bit having a wire holding portion in substantial alignment with the wire-receiving groove of the ICe bit thereby obviating lateral bending of the wire in order to effect holding engagement with the sleeve.

Yet another object is to provide an improved wire wrapping device into which a wire can be loaded in a more simple and time saving manner than has been possible heretofore.

Still another object is to provide a wire wrapping device having an improved bit sleeve for holding a wire so that no portion of the wire projects outwardly from the sleeve.

These and other more detailed objects and advantages will appear upon reading the following detailed description and claims and upon considering in connection therewith the attached drawings in which:

FIG. 1 is a side elevational view of a wire wrapping tool incorporating a bit and sleeve which embody the present invention;

FIG. 2 is an enlarged isometric view of the front end of the bit and sleeve shown in FIG. 1;

FIG. 3 is a view in perspective of a wire bound joint between a pair of terminals;

FIG. 4 is an enlarged end elevational view of the bit I and sleeve shown in FIGS. 1 and 2;

the sleeve for interfitting FIG. 5 is a fragmentary sectional view taken substantially along lines 5-5 of FIG. 4;

FIG. 6 is a view similar to FIG. 4 wherein said bit is rotated clockwise through FIG. 7 is a fragmentary sectional view'taken substan tially along lines 77 of FIG. 6;

FIG. 8 is a view similar to FIGS. 4 and 6 wherein the bit has been rotated through several revolutions;

FIG. 9 is a fragmentary sectional view taken substantially along lines 99 of FIG. 8; and

FIG. 10 isv a fragmentary plan view of the sleeve with a portion thereof broken away to show details of the wire holding slot.

The illustrative embodiment of the invention shown in the drawings is drivably attached to a rotary power tool designated in its entirety in FIG. 1 by numeral 10. Reference may be had to US. Patent 3,078,052 for a description of the structural and operational features 'of the tool 10. For the purpose of describing the coaction of tool 10 with the present invention, it is sufiicient to say that a sleeve 12 is removably secured within the nose portion of tool 16 by a collet 14 and collet nut 16; and, a wrapping bit 18 is rotatably journalled within sleeve 12 and has an enlarged end 19 projecting rearwardly from ing member 20 of tool 10. From the following description of the invention, it will be apparent to those familiar with wire wrapping devices that the illustrative tool 10 may be replaced by any of several known rotary tools of this class or by a suitable manually operated means.

The sleeve 12 comprises an elongated cylinder having an mside diameter substantially corresponding to the outside diameter of the bit 18. Abutment of the enlarged bit end 19 with the extreme rear end of the sleeve prevents axial displacement of the ,bit forwardly within the sleeve; and, as shown in FIG. 5, for example, the bit and sleeve are so dimensioned that the front or forward end of bit 18 is somewhat recessed within the sleeve 12. An im portant aspect of this invention is accomplished by lip 22 which is integrally formed at the forward end of sleeve 12 and which will be hereinafter described in detail.

Bit 18 comprises an elongated shaft having a longitudinal bore or recess 24 opening axially to its forward end face 26 for receiving therein the free end of a terminal post, or the like, substantially in the manner shown in FIGS. 4 9.- Radially offset from and'parallel to the recess 24 is a groove 28 opening to the outer cylindrical surface of bit 18. Groove 28 opens axially forwardly to the bit face 26 and is intended to receive an end portion of a wire 30 substantially in the manner shown in FIGS.

engagement with a rotary driv- 3 r 4 and 5. Preferably, the bit face 26 comprises axially spaced inner and outer surfaces, 32 and 34 respectively,

which are joined by a sloped wire camming surface 36.

The illustrative bit face configuration and the coaction of the bit face with a wire being wound about a terminal are described in detail in the aforementioned US. Patent 3,078,052. Since the illustrated bit face is, however, merely an example, it will be understood that many types of known bit constructions may be used to advantage in connection with this invention.

As noted hereinabove, an object of this invention is to provide improved wire wrapping means for making socalled bound joints of the type illustrated in FIG. 3 of the drawings. In making this type of joint, a wire, such as the aforementioned wire 30, is wound or wrapped in tight, helical convolutions about a pair of rectangular terminals 38 and 40 having their wider faces in contact. The terminals may project from an insulating terminal board 42 which restrains the terminals against rotation as the wire 30 is wound thereabout. As'in most wire wrapping applications, the sharp edges of the terminals andthe wire are matingly deformed during the wrapping operation to produce a joint having good electrical contact and mechanical stability. While the present device is primarily intended to join electrical terminals together, it

will be appreciated that a device of this character may be employed to make wire bound connections between nonelectrical members of suitable size and shape.

In order to wrap a wire about the terminals 40 and 42 received in bit recess 24, the wire 30 in hit groove 28 must have that portion 44 which extends axially forwardly from groove 23 secured against rotation with the bit 18; otherwise, rotation of the bit with respect to the terminals will not effect withdrawal of the wire 30 from the wire-receiving groove 28 and winding of the wire about the terminal in the manner shown in FIGS. 8 and 9. Heretofore, such securement of a wire has been effected by manually bending a portion of the wire radially outwardly over the forward end of a sleeve and seating the wire in a notch formed in the end of the sleeve or by manually gripping the wire during the wrapping operation. The aforementioned US. Patent 3,078,052 discloses a typical sleeve having a notch at the forward end thereof for seating and holding the wire. -It will be apparent that that end portion of the wire held in either manner above described will not be wrapped closely about the terminal, but will, instead, project laterally from the terminal and the convolutions of the connection. I Since wardly over and beyond the end of the sleeve, a so-called pigtail of substantial length will be formed; and it is usually necessary to treat such a pigtail by a bending or cutting operation to avoid interterminal shorting where pairs of terminals are closely spaced on a terminal board. The present invention contemplates the provision of the aforementioned lip 22 for engaging and holding portion 44 of wire 30 during the wrapping operation in such a manner that the resulting pigtail, shown at numeral 46 in FIGS. 3 and 9, will be reduced to a minimum length and will be bent forwardly in longitudinal alignment with the terminals 38 and 40. present invention, no time consuming, therefore costly, follow-up operations need be performed on the pigtail 46. i

As best seen in FIG. 2, the lip 22 is integrally formed on the forward end of sleeve 12; and, as viewed in transverse cross section perpendicular to the longitudinal axis of the sleeve, comprises a segment of a circle. The armate surface 48 of lip 22 is a continuation of a portion of the outer cylindrical surface of the sleeve 12; and, the chordal surface 50 and the extreme forward lip surface 52 are disposed at right angles to one another. The lip may be said to depend radially from the arcuate surface 48 to place the chordal lip surface 50 in substantial registration with the bottom of the wire-receiving groove 28 In most applications of the when the sleeve and bit are disposed in the relative rotative positions shown in FIGS. 2, 4 and 5, for example.

A wire-holding slot 54 opens centrally and radially inwardly to the chordal lip surface 50 and extends the full axial length of lip 22. The slot wall is parallel with the longitudinal axes of the sleeve .12 and the bit 18 and opens forwardly to lip surface 52 in a countersunk surface 58. The slot 54 extends radially into lip 22 to a depth permitting substantial axial alignment with the wire receiving groove 28 when the bit 18 is rotated relative to. the sleeve to the position shown in FIGS. 2, 4 and 5.

Usually power tools such as tool 10 include an indexing means, not shown, which would beoperable to align the groove 28 with slot 54 following each wrapping cycle.

The wire holding feature of lip 22 can be best understood by having reference to FIGS. 4-10 which show the relative positions of. the sleeve 12, bit 18 and wire 30 at successive stages of the wrapping cycle. After the wire 30 has been cut to a predetermined length to provide the desired number of wrapped convolutions, usually three to twelve, the wire is inserted axially throughthe slot 54 i into the aligned bit groove 28 as shown in FIG. 5. The countersunk surface 58 serves to guide the wire into the slot to facilitate rapid and efficient wire loading. To minimize the length of the pigtal'l 46, it is preferable that the extreme forward end of wire 30 be flush with the forward lip surface 52. After the loading operation is completed, the tool 10 is advanced with respectto the terminal board 42 to locate the terminals 38 and 40 within the bit recess 24. As the bit 18 begins to rotate in response to actuation of tool 10, the forward end 44 of wire 30 will be held against rotation by the lip 22 due to vertically and laterally cocking of the wire between the spaced wall portions of the slot 54 substantially in the manner shown in FIG. 10. Such cocking of the wire effectively resists the tendency of portion 44 to be drawn axially rearwardly and radially inwardly over an abrupt edge 60 defined at the opening of slot 54 to the chordal.

lip surface 50. Instead, as shown in FIGS. 6, 7 and 10, wire portion 44 will bend sharply about the edge 60 forming a kink indicated on wire 30 at letter A. The aforedescribed cocking and kinking of wire portion 44 is effective to resist the pull acting on wire portion 44 due to the dragging and bending of the wire 30 at point B'as it emerges from the groove 28. This pull on wire portion 44 tending to dislodge it from slot 54 is substantially isolated from portion 44 as soon as the wire 30 engages at point C with a sharp corner of terminal 38 as shown in FIG. 6. The resulting mating deformation of the wire and terminal at point C and at each succeeding corner of the terminals provides secure mechanical attachment between the wire and the terminals usually before one complete convolution is formed about the terminals;- therefore, it is permissible that. the initial holding en-.

gagement between slot 54 and wire portion 44 be released in advance of completion of the wrapping operation.

terminals 38 and 40 thereby reducing the lateral projec tion of the pigtail from the completed joint.

In order to effect the aforementioned cocking of wire portion 44 within slot 54, it is preferred that the axial dimension of the slot be at least twice the wire diameter, and that the width of slot 54 substantially correspond to the wire diameter. These dimensional relationships between the slot 54 and the wire 30 have proven satisfactory where wire sizes from 20 gauge to 30 gauge have been employed. Preferably, the outer bit surface 34 is recessed with respect to the forward end of sleeve 12 and the inner bit surface 32 is recessed with respect to the outer bit surface 34 in order to achieve camming of the wire convolutions by surface 36, as shown in FIG. 9; without destructive interference between any portion of the bit face 26 and the Wire 30 as the latter is cocked and kinked as aforedescribed.

From the foregoing it will be apparent that a wire holding lip constructed in accordance with the teachings of the present invention may be integrally formed on the sleeve by simple machining operations without a significant increase in the cost of manufacture of standard sleeves. Moreover, the lip 22 performs its intended function without the use of moving parts thereby obviating the need for periodic adjustments or replacements of parts. Furthermore, no new operator skills need be acquired for using this improved bit sleeve.

It will be understood that the above description and accompanying drawings comprehend only general and preferred embodiments of the invention and that various changes in construction, proportion, material and arrangement of the elements thereof may be made without sacrificing any of the above enumerated advantages or departing from the scope of the appended claims.

Having fully described the invention what is claimed as new and useful is:

1: In a wire Wrapping device including a cylindrical sleeve having a forward end; a wrapping bit rotatably journalled in said sleeve and having a forward end adjacent the forward end of said sleeve; said bit having a longitudinal terminal-receiving recess and a radially oifset wire-receiving groove opening to the forward end thereof; the improvement comprising: means for engaging a forwardly projecting end portion of a wire received in said groove and for releasably holding said end portion against rotation with said bit as the latter is rotated about its rotative axis; said means comprising an integral lip portion of said sleeve projecting axially from the forward end thereof and defining a slot for receiving said projecting end portion of said wire; a cross section through said lip portion perpendicular to the longitudinal axis of said sleeve comprising a segment of a circle having said slot opening normal to and at the midpoint of the chordal side of said segment; and said slot opening radially from said lip portion toward the rotative axis of said bit and opening axially to the forward end of said bit in substantial alignment with said wire-receiving groove.

2. In a wire wrapping device including a cylindrical sleeve having a forward end; a wrapping bit rotatably journalled in said sleeve and having a forward end adjacent the forward end of said sleeve; said bit having a longitudinal terminal-receiving recess and a radially ofiset wire-receiving groove opening to the forward end thereof; the improvement comprising: means for engaging a forwardly projecting end portion of a wire received in said groove and for releasably holding said end portion against rotation with said bit as the latter is rotated about its rotative axis; said means comprising an integral lip portion of said sleeve projecting axially from the forward end thereof and defining a slot for receiving said projecting end portion of said wire; said slot opening radially from said lip portion toward the rotative axis of said bit and opening axially to the forward end of said bit in substantial alignment with said wire-receiving groove; and said slot having at its forward end a countersunk wall surface.

3. In a wire wrapping device including a cylindrical sleeve having a forward end; a wrapping bit rotatably journalled in said sleeve and having a forward end adjacent the forward end of said sleeve; said bit having a longitudinal terminal-receiving recess and a radially offset wire-receiving groove opening to the forward end thereof; the improvement comprising: means for engaging a forwardly projecting end portion of a wire received in said groove and for releasably holding said end portion against rotation with said bit as the latter is rotated about its rotative axis; said means comprising an integral lip portion of said sleeve projecting axially and radially from References Cited by the Examiner UNITED STATES PATENTS 6/1954 Miloche 242--7 X 2/ 1963 Olds et al 242-7 M-ERVIN STEIN, Primary Examiner.

B. S. TAYLOR, Assistant Examiner. 

3. IN A WIRE WRAPPING DEVICE INCLUDING A CYLINDRICAL SLEEVE HAVING A FORWARD END; A WRAPPING BIT ROTATABLY JOURNALLED IN SAID SLEEEVE AND HAVING A FORWARD END ADJACENT THE FORWARD END OF SAID SLEEVE; SAID BIT HAVING A LONGITUDINAL TERMINAL-RECEVING RECESS AND A RADIALLY OFFSET WIRE-RECEIVING GROOVE OPENING TO THE FORWARD END THEREOF; THE IMPROVEMENT COMPRISING: MEANS FOR ENGAGING A FORWARDLY PROJECTING END PORTION OF A WIRE RECEIVED IN SAID GROOVE AND FOR RELEASABLY HOLDING SAID END PORTION 